Main Article Content
The world’s fossil fuel resources are limited and are getting depleted rapidly. Most of the current energy demands are fulfilled by fossil fuels and the related implications due to the rise in greenhouse gas emissions is a major concern . Hence, the use of renewable energy sources should be encouraged. Hydrogen is an important alternative to other energy sources which is clean and abundant . Hydrogen is used in many industries starting from refineries to chemicals. The global demand for hydrogen has escalated over the decades, from around 20MT (Million Tons) in 1975 to around 70MT in 2018. Yet, most of the hydrogen production is through fossil fuels and its costs range from 1 to 3 USD per kg. This must change because an energy transition is taking place to reduce the emission of greenhouse gases and to combat climate change. Recent advancement in this field includes the production of green hydrogen, a new ally for a zero-carbon future . The development of efficient hydrogen storage systems plays an important role in the adaptation of hydrogen as an alternate fuel. However, hydrogen is considerably difficult to handle given its small size, high volatility, flammability, lowest energy density (per unit volume), and the fact that it travels with the velocity of sound. These properties of hydrogen lead to its permeation through several materials that are impermeable to other gases. This permeation and trapping lead to the generation and propagation of cracks in carbonaceous materials which is termed hydrogen embrittlement. It also results in the degradation of mechanical properties such as ductility, tensile strength, fatigue strength, and fracture toughness of the materials. This ushers the search for hydrogen impermeable materials.
Processes like cathodic charging, electroplating, and welding allow hydrogen to enter metals and alloys . High strength materials such as high strength steels, high Manganese steel, aluminum, titanium, and magnesium alloys of steel are most vulnerable to hydrogen embrittlement. The factors that affect hydrogen embrittlement include gaseous and dissolved sources of hydrogen, residual or applied stress, material susceptibility, exposure time, type and production method of the alloy, number of discontinuities, heat treatment method, etc. The prevention of embrittlement focuses on two approaches, one being surface treatment methods (such as surface coatings, surface modification) and the other being the modification of the microstructure of materials, which includes the addition or elimination of suitable alloy elements . Alternative options include the use of lower strength steel, low hydrogen plating, and minimization of applied and residual stress.
Hydrogen storage is very important when it comes to the usage of hydrogen on a large scale. This could either be for stationary or for mobile applications. The stationary applications include storage on-site at points of use or production and power generators. The mobile applications are hydrogen transportation and vehicle fuels. Hydrogen storage is currently done in different ways such as a compressed gas using metallic heavy steel containers, steel vessels with glass fiber composite overwraps, full composite wrap with metal lining, and fully composite storage systems. However, steels are heavy and occupy a lot of space, whereas composites are expensive . Also, the durability of the current materials used is not up to the mark. Therefore, lightweight, compact, and durable materials must be made to increase the lifespan of the hydrogen storage systems. The energy efficiency must be increased as the energy used to get hydrogen in and out is more than that of the fuel itself. The low density of hydrogen even at extreme pressures and temperatures results in a low energy per unit volume. So, storage methods having more potential for greater energy density (per unit volume) must be developed. Other challenges are long refueling times and a lack of analysis of the full life-cycle cost and efficiency for current storage systems. Overcoming these challenges can help increase vehicle range and bring down the overall cost of storage if hydrogen impermeable materials with better properties are created. This is ultimately expected to facilitate the desired shift to green hydrogen technology.
How to Cite
Hydrogen Storage, Hydrogen Impermeable Materials, Hydrogen Embrittlement
 Ramin Moradi, Katrina M. Groth, Hydrogen storage and delivery: Review of the state of the art technologies and risk and reliability analysis, International Journal of Hydrogen Energy, Volume 44, Issue 23, 2019, Pages 12254-12269.
 Noussan, M.; Raimondi, P.P.; Scita, R.; Hafner, M. The Role of Green and Blue Hydrogen in the Energy Transition: A Technological and Geopolitical Perspective. Sustainability 2021, 13, 298.
 Sandeep Kumar Dwivedi, Manish Vishwakarma, Hydrogen embrittlement in different materials: A review, International Journal of Hydrogen Energy, Volume 43, Issue 46, 2018, Pages 21603-21616.
 Li, X., Ma, X., Zhang, J. et al. Review of Hydrogen Embrittlement in Metals: Hydrogen Diffusion, Hydrogen Characterization, Hydrogen Embrittlement Mechanism and Prevention. Acta Metall. Sin. (Engl. Lett.) 33, 759–773 (2020).